CHAPTER
Introduction 1-1
1
Introduction
This manual describes the features and functions of Release 3.0 of the Cisco MGX™ 8220 edge
concentrator. (See Figure 1-1.)
Figure 1-1 MGX 8220 Edge Concentrator
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MGX 8220 System Overview
Cisco MGX 8220 Reference
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MGX 8220 System Overview
The MGX 8220 shelf is designed on the philosophy that large scale deployment of narrowband and
medium-band servicesis best handled using an ATM infrastructure. In fact, supportof theseservices
can, by themselves, justify an ATM infrastructure. The same infrastructure can then be used to
provide broadband services to customers when and where they are needed.
The MGX 8220 shelf is an adjunct shelf to the Cisco BPX® 8600 series wide-area switch.
Architecturally it provides:
• A means for flexibly providing many narrowband and/or medium-band ATM and non-ATM
service interfaces without consuming BPX switch slots.
• Conversion of non-ATM traffic streams to and from ATM traffic streams usingAdaptation Layer
standards.
• A means for concentrating the traffic from the narrowband and/or medium-band interfaces onto
the broadband ATM ports of the BPX switch.
Service Interfaces
The MGX 8220shelf isa flexible standards-based service access platform.The MGX 8220 shelf can
support a wide range of services over narrowband and mid-band user interfaces, mapping all the
service traffic to and from ATM, based upon standardized interworking methods. The aggregated
trafficis sent/receivedoveran ATM interfaceto an ATM switch (BPX switch), using up a single port
on the ATM switch.
Release 3.0 of the MGX 8220 shelf supports up to 40 channelized or non-channelized T1 and E1
interfaces on a single shelf providing support for Frame Relay UNI and NNI; ATM UNI, NNI, and
FUNI; Frame Relay to ATM network interworking; Frame Relay to ATM service interworking and
circuit emulation services. The MGX 8220 shelf Release 3.0 also supports the use of Inverse
Multiplexing for ATM (IMA) to provide ATM trunking below T3/E3.
The system’s modular, software-based architecture enables it to support these and other additional
user services in the future, through downloadable software upgrades or new hardware modules.
Standards-Based Conversion to ATM
All user information received by MGX 8220 interfaces is converted into 53-byte ATM cells, using
standard ATM Adaptation Layers (AALs), for transport over the ATM backbone network. Cell
segmentation and reassembly (SAR) and other adaptation functions are distributed to each interface
module to eliminate system bottlenecks.
• For Circuit Emulation Services, AAL1 is used.
• For Frame Relay (FR to ATM network interworking), AAL5 and FR-SSCS (Frame Relay
Service Specific Convergence Sublayer) are used.
• For Frame Relay to ATM service interworking, both transparent and translation modes are
supported to map FR to native ATM AAL5.
• For Frame Forwarding, AAL5 is used.
Introduction 1-3
MGX 8220 Shelf
Aggregation of Traffic into ATM Networks
Each MGX 8220 shelf connects to the BPX switch across a T3 or E3 ATM STI (Cisco Trunk
Interface) to a BNI module on the BPX switch. Thus, the MGX 8220 shelf Release 3.0 supports
aggregationof traffic up to 40 T1 or E1 access ports or up to 1240 64-Kbps subscribers, onto a single
T3 or E3 trunk, using only a single port on the BPX switch.
In this release, the MGX 8220 shelf should normally be collocated with the BPX switch. Figure 1-2
shows how the MGX 8220 shelf usage is envisioned in Release 3.0.
Figure 1-2 MGX 8220/BPX Switch Relationship
For remote locations with limited bandwidth needs, the MGX 8220 shelf can be remoted from the
BPX switch using IMA trunk machines. (See Figure 1-3.)
Figure 1-3 Remote Cisco MGX 8220 Configuration
The following sections provide an overview of the MGX 8220 shelf, the Release 3.0 cards, and
management capabilities. In-depth details are provided in subsequent chapters.
MGX 8220 Shelf
Physically, the MGX 8220 shelf consists of cards in a 19 inch rack mountable shelf.
The shelf can be powered either from a -48VDC source or from a 220V AC source. The DC version
includes DC power entry modules that can be mounted in the shelf. The AC version requires an
external rack mounted AC Power Module. Both versions require a rack mounted cooling assembly.
Multiple MGX 8220 shelves can be mounted in the same rack, sharing power and cooling
assemblies.
The MGX 8220 shelf contains 16 slots where each slot can accommodate a front card and a back
card. The front row is used for function modules, cards that perform more complex functions within
the unit (for example, frame relay to ATM conversion). The back row isused for line modules, cards
that provide interfaces to one or more transmission lines connected to the MGX 8220 shelf (for
example, the trunk line to the BPX switch or an RS-232 line to a control terminal).
40 T1 or E1
service interface
lines
MGX 8220
BPX 8620
Broadband
ATM
service
T3 ATM STI
connection
H8239
40 T1 or E1
service interface
lines
MGX 8220
BPX 8620
Broadand
ATM service
IMATM
Long distance
IMA trunk
T1 or E1 service
interface lines
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MGX 8220 System Overview
Cisco MGX 8220 Reference
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MGX 8220 Cards
MGX 8220 cards are always installed as a pair consisting of a front card (function module) and a
matching back card (line module) in the same slot, except for the SRM-T1E1 card which only has a
front card. Communication between slots is achieved through buses in the shelf backplane.
Release 3.0 consists of the following module pairs:
• MGX 8220 Shelf Controller(ASC)
This is a pair of cards providing overall control of the shelf and providing line interfaces to
maintenance and control ports which are used for user configuration and management of the
shelf.
• Broadband Network Module (BNM-T3)
This is a pair of cards which together provide the interface to the attached BPX switch over a T3
ATM interface.
• Broadband Network Module (BNM-E3)
This is a pair of cards which together provide the interface to the attached BPX switch over a E3
ATM interface.
• Frame Service Module for T1 (FRSM-4T1)
This card provides interfaces for up to four T1 lines, each of which can support one 56 kbps or
one Nx64 kbps FR-UNI, FR-NNI port, ATM-FUNI, or Frame Forwarding port.
• Frame Service Module for T1 channelized (FRSM-4T1-C)
This card provides interfaces for up to four T1 lines, each of which can support multiple
(up to 24) 56 kbps or Nx64 kbps FR-UNI, FR-NNI, ATM-FUNI, or Frame Forwarding port.
• Frame Service Module for E1 (FRSM-4E1)
This card provides interfaces for up to four E1 lines, each of which can support one 56 kbps or
one Nx64 kbps FR-UNI, FR-NNI, ATM-FUNI, or Frame Forwarding port.
• Frame Service Module for E1, channelized (FRSM-4E1-C)
This card provides interfaces for up to four E1 channelized frame relay lines, each of which can
support multiple (up to 31) 56 kbps or Nx64 kbps FR-UNI, FR-NNI, ATM-FUNI, or Frame
Forwarding port.
• ATM UNI Service Module for T1 (AUSM-4T1)
This card provides interfaces for up to four T1 lines, each of which cansupport one T1 ATM UNI
or ATM NNI.
• ATM UNI Service Module for E1 (AUSM-4E1)
This card provides interfaces for up to four E1 lines, each of which cansupport one E1 ATM UNI
or ATM NNI.
• Circuit Emulation Service Module for T1 (CESM-4T1)
This card provides interfaces for up to four T1 lines, each of which is a 1.544 Mbps unstructured
synchronous data stream.
• Circuit Emulation Service Module for E1 (CESM-4E1)
This card provides interfaces for up to four E1 lines, each of which is a 2.048 Mbps unstructured
synchronous data stream.
• Inverse Multiplexing for ATM Trunk Module—T3 to T1 (IMATM-T3-T1)
This card acts as an extension of the BPX BNI card and permits the BPX ATM trunk to be used
over multiple (up to 8) T1 lines instead of a single T3 line.
• Inverse Multiplexing for ATM Trunk Module—E3 to E1 (IMATM-E3-E1)
This card acts as an extension of the BPX BNI card and permits the BPX ATM trunk to be used
over multiple (up to 8) E1 lines instead of a single E3 line.
Introduction 1-5
MGX 8220 Management
• Service Resource Module (SRM-T1E1)
This card provides loopback and bit error rate testing (BERT) functions and 1:N redundancy for
the service modules.
The ASC and the BNM modules must be present in an MGX 8220 shelf and are referred to as the
core modules. The MGX 8220 shelf release 3.0 supports redundant core modules where one
ASC/BNMset is anactive setand a second ASC/BNMis a standbyset. In the eventofa malfunction,
the standby set automatically takes over as the active set. The SRM is optional. If present, it is part
of the core card set, with switchover to the standby upon a malfunction of the active BNM or ASC.
MGX 8220 Management
Thefunctions and operation of theMGX8220shelf are achievedthroughdownloadedfirmware.The
firmware controls the overall operation of the shelf and responds to configuration and other
commands received from a user terminal or workstation. The MGX 8220 shelf has a command
repertoire of over60 user commands which are used to configure and display the various operational
parameters of the shelf.
The current status and configuration parameters of the MGX 8220 modules are maintained in a
Management Information Base (MIB) which is updated by the firmware as changes in status and
configuration occur. The MIB can be interrogated using SNMP commands.
Most of the functions of the MGX 8220 shelf Release 3.0 can be effected through the graphical user
interface provided in StrataView Plus 8.2.
The ASC module includes three ports for user input of management commands. A further means of
management access is provided in-band over the ATM trunk.
The maintenance port is a simple RS-232 port for direct connection to an alpha-numeric terminal
into which the user can type commands through a Command Line Interface (CLI).
The control port (SLIP protocol only), the LAN (Ethernet) port and the In-band ATM connection all
support the CLI (via Telnet), TFTP and SNMP protocols for communicating with the MGX 8220
shelf.
New in Release 3.0
This section provides a very brief description of the new MGX 8220 shelf features that have been
added since Release 2.x.
• A new Broadband Network Module is available which supports E3 trunking to the BPX switch.
• The new Circuit Emulation Service Modules (CESM) provide support for unstructured
synchronous data streams on both T1 and E1 lines.
• The Frame Service Module (FRSM) adds support for frame forwarding on a port-by-port basis.
• The ATM UNI Service Module (AUSM) now supports a number of new features including SRM
BERT support, enhanced CAC (Connection Admission Control), and Virtual Path Connection
capability.
• The optional SRM (Service Resource Module) which provides for loopback and BERT testing
of lines and ports now provides 1:N redundancy for service modules as a feature license.
• The new Inverse Multiplexing for ATM Trunk Module 0- (IMATM) permits BPX nodes to use
multiple (up to 8) T1 or E1 lines as ATM trunks instead of a single T3 or E3 line. This card is
housed in the MGX 8220 shelf but acts as an extension to the BPX BNI card.
New in Release 3.0
Cisco MGX 8220 Reference
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